Don't have one myself but I hear they are great. I have a bump buster on my gun and everybody that shoots it has good things to say. The best part is Ken is a first class craftsman and a hell of a nice guy. He will stand behind his work. If your close to San Antonio I know Ken has an 1100 w/an AB on it and I'm sure you could try it out.
Jimmy

FLAKETM, I bought a new 391 and used it as the test bed when I was developing the Auto-Buster. I find the recoil from a 391 uncomfortable. The Auto-Buster tames it well. I've installed a lot of them for 391 shooters since then with great results.